<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>

    <style>
        .box1 {
            width: 100px;
            height: 100px;
            background: red;
            /* no-report，显示会拉伸 */
            /* background: url("images/001.jpg") no-repeat; */
            /* background: url(images/001.jpg) no-repeat; */
            /* border: 10px solid black; */
            border-top: 10px solid green;
            border-left: 10px solid yellow;
            border-bottom: 10px solid pink;
            border-right: 10px solid blue;
            /* float: right; */
        }

        .box2 {
            width: 300px;
            height: 300px;
            background: blue;
        }

        .box3 {
            width: 100px;
            height: 100px;
            background: yellow;
            float: left;
        }

        .box4 {
            width: 100px;
            height: 100px;
            background: green;
            float: right;
        }
    </style>
</head>
<body>
    
    <div class="box1">
        嘻嘻
    </div>
    
    <div class="box2">
        <div class="box3"></div>
        <div class="box4"></div>
    </div>

</body>
</html>